.\"	$NetBSD: newfs_lfs.8,v 1.24 2015/10/15 06:24:33 dholland Exp $
.\"
.\" Copyright (c) 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)newlfs.8	8.1 (Berkeley) 6/19/93
.\"
.Dd October 13, 2015
.Dt NEWFS_LFS 8
.Os
.Sh NAME
.Nm newfs_lfs
.Nd construct a new LFS file system
.Sh SYNOPSIS
.Nm
.Op Ar newfs_lfs-options
.Ar special
.Sh DESCRIPTION
.Nm
builds a log-structured file system on the specified special
device basing its defaults on the information in the disk label.
Before running
.Nm
the disk must be labeled using
.Xr disklabel 8 ,
the proper fstype is 4.4LFS.
Reasonable values for the
.Li fsize ,
.Li bsize ,
and
.Li sgs
fields are 1024, 8192, and 7 respectively.
.Pp
The following options define the general layout policies.
.Bl -tag -width Fl
.It Fl A
Attempt to compute the appropriate segment size using the formula
.Em 4 * bandwidth * access time .
The disk is tested for twenty seconds
to discover its bandwidth and seek time.
.It Fl B Ar logical-segment-size
The logical segment size of the file system in bytes.
If not specified, the segment size is computed by left-shifting
the partition label's block size by the amount indicated in the
partition table's segshift.
If the disklabel indicates a zero block size or segment shift,
a compile-time default segment size of 1M is used.
.It Fl b Ar block-size
The block size of the file system in bytes.
If not specified, the block size is taken from the partition label,
or if the partition label indicates 0,
a compile-time default of 8K is used.
.It Fl F
Force creation of an LFS even on a partition labeled as another type.
.Nm
will use compile-time default values for block and fragment size, and segment
shift, unless these are overridden by command-line flags.
.It Fl f Ar fragment-size
The fragment size of the file system in bytes.
If not specified, the fragment size is taken from the partition label,
or if the partition label indicates 0,
a compile-time default of 1K is used.
.It Fl I Ar interleave
Specify the interleave between segments.
The default is zero.
.It Fl i
The size of an inode block, in bytes.
The default is to use the same size as a fragment,
or in a v1 filesystem, the same size as a data block.
.It Fl L
Create a log-structured file system (LFS).
This is the default, and this
option is provided for compatibility only.
.It Fl M Ar nsegs
Specify
.Em lfs_minfreeseg ,
the number of segments left out of the amount allocated to user data.
A higher number increases cleaner performance, while a lower number
gives more usable space.
The default is based on the size of the filesystem, either 5% of the
total number of segments or 20 segments, whichever is larger.
.It Fl m Ar free space \&%
The percentage of space reserved from normal users; the minimum
free space threshold.
The default value used is 10%.
.It Fl N
Do not actually create the filesystem.
.It Fl O Ar offset
Start the first segment this many sectors from the beginning of the
partition.
The default is zero.
.It Fl R Ar nsegs
Specify
.Em lfs_resvseg ,
the number of segments set aside for the exclusive use of the cleaner.
A larger figure reduces the likelihood of running out of clean segments,
but if
.Em lfs_resvseg
is too close to
.Em lfs_minfreeseg ,
the cleaner will run without ceasing when the filesystem becomes close to
full.
The default is the larger of 15 or the quantity
.Em lfs_minfreeseg
/ 2 + 1 .
.It Fl r Ar ident
For a v2 filesystem, specify the roll-forward identifier for the
filesystem.
This identifier, a 32-bit numeric quantity,
should be different from that of any LFS that may previously
have existed on the same disk.
By default the identifier is chosen at random.
.It Fl s Ar size
The size of the file system in sectors.
.It Fl v Ar version
Make a filesystem with the specified disk layout version.
Valid options are 1 or 2 (the default).
.Em Note ,
however, that LFS version 1 is deprecated, and 64-bit volumes may not
be version 1.
.It Fl w Ar bitwidth
Create a filesystem using the specified bit width: 32 or 64.
32-bit LFS volumes are limited to 2TB in size; 64-bit LFS volumes are
not, but incur additional overhead from having larger metadata
structures.
The default is 32-bit for volumes less than 1 TB, and 64-bit for
larger volumes.
.El
.Sh SEE ALSO
.Xr disktab 5 ,
.\" .Xr fs 5 ,
.Xr disklabel 8 ,
.Xr diskpart 8 ,
.Xr dumplfs 8
.\" .Xr tunefs 8
.Rs
.%A M. Seltzer
.%A K. Bostic
.%A M. McKusick
.%A C. Staelin
.%T "An Implementation of a Log-Structured File System for UNIX"
.%J "Proceedings of the Winter 1993 USENIX Conference"
.%D January 25-29, 1993
.%P pp. 315-331
.Re
.Rs
.%A J. Matthews
.%A D. Roselli
.%A A. Costello
.%A R. Wang
.%A T. Anderson
.%T "Improving the Performance of Log-Structured File Systems with Adaptive Methods"
.%J "Proceedings of the Sixteenth ACM SOSP"
.%D October 1997
.Re
.Sh HISTORY
A
.Ic newlfs
command appeared in
.Bx 4.4 ,
and was renamed to
.Nm
for
.Nx 1.4 .